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w. R. EWING June' 16, 1936.

METHOD FOR REFORMING CUTTERS FOR HYDRAULIC DREDGES Filed May 2, 1935 of a number of Patented June 16, 1936 UNHTED STATES @EFEQE Williard Rea Ewing,

Libertyville, Ill., assignor to McWilliams Dredging Company,

Chicago, 111.,

a corporation of Illinois Application May 2, 1935, Serial No. 19,418

1 Claim.

This invention relates to hydraulic dredging machines and more particularly to the method of making the cutters thereof.

Cutters for hydraulic dredges usually consist blades mounted for rotation about a common shaft, the blades having a peculiar shape and curvature based largely on empirical data.

As these cutters are used, they often become Worn and battered until they are unfit for further use. Where excavating in material which has high abrasive properties, certain types of cutters have been found to last only a few weeks and since the price of a cutter may be hundreds of dollars, the cost of operation is materially affected.

Prior to the present invention, the practice has generally been to discard the cutters after they have become worn, although in certain types of cutters, where the individual blades are secured, as by bolts, to a frame, as a hub and supporting spider, provision has been made to save this frame. This effected but little economy, however, since the cost of the frame is a minor item compared to the cost of the blades, which, be-

cause of their very peculiar shape and because they must be highly resistant to wear, are very difiicult to fabricate. Moreover, the bolting on of new blades for old has been impossible in that 30 kind of cutter Where there is no central spider and since this kind of cutter operates more efficiently than any other on certain types of work, because of its open nature, it has frequently been used even though its life is short and it must be 35 wholly replaced when worn out.

It is one object of the present invention to reduce the cost of maintenance of a suitable cutter on a hydraulic dredge by removing and replacing only a small portion thereof when it becomes 40 worn.

It is a further object of the invention to provide novel method for replacing a worn out part of a cutter for a hydraulic dredge.

Other objects and advantages reside in certain novel features as will be apparent from the following description taken in connection with the accompanying drawing in which:

Figure 1 is a side perspective view of a known kind of cutter with means thereon illustrating 50 the first step in the process of removing a worn part from the cutter and substituting a new one therefor;

Figure 2 is a similar view of the same cutter with a portion of each blade cut off and indicating the second step of the process;

Figure 3 is a similar view of the same cutter after the process has been completed;

Figure 4 is a perspective view of a templet used for marking the blades;

Figure 5 is a transverse cross-sectional view of one of the blades with the templet of Figure 4 in position thereon and illustrating a marker in position;

Figure 6 is a transverse cross-sectional view of a blade after the portion outside the templet of Figure 5 has been cut off Figure 7 is a transverse cross-sectional view of a blade after a new cutting edge has been secured to the blade, the view showing a positioning templet in position on the blade; and.

Figure 8 is a perspective view of a cutting edge adapted to be secured to a blade.

Referring to the drawing in detail, a cutter is shown in Figure l as consisting of a number of ciu'ved blades H one end of each of which is secured to a hub l2 while the other end of each is secured to a spacing ring 53. This type of cutter is well known, being of that type in which no spider or radially extending spokesare provided for strengthening the assembly. The present invention is particularly applicable to this type of cutter, but it is to be understood that the invention may be used in connection with other cutters as well.

During use, such a cutter becomes worn or bent. Because the wearing may take place irregularly or the cutting edges, indicated at I4, on the blade become badly bent or broken in a wide variety of ways, no attempt has been made to illustrate this condition on the drawing, and the invention will be described as though applied to a cutter of regular shape.

Instead of discarding the entire cutter after it has become worn with use, in accordance with the present invention, the cutting edge, together with a portion of the blade adjacent thereto is carefully removed and a new portion and cutting edge welded or otherwise secured to the main body of the blade.

In order to properly mark the blade for cutting a templet l5, shown in Figure 4, is provided. This templet is designed to fit snugly upon the rear portion of a blade, as illustrated in Figure l, leaving the forward portion projecting from under it. In order to properly position the templet, it is provided with a depending flange I 6 adapted to rest against the rear of a blade.

The templet I5 is of such a shape that its forward edge is parallel to and a short distance to the rear of the original cutting edge of the blade upon which it may be positioned.

With the templet in position a marker may be moved along the forward edge of the templet, as indicated in Figure 5, the mark made upon the blade indicating how much is to be removed. Since the wearing or battering of the blades occurs almost entirely on the cutting edge and adjacent portion of each blade, if this part is removed and replaced, the cutter is as good as new.

Accordingly, after the blades have been marked as indicated above, the templet is removed and an acetylene torch or other cutting device applied along the mark so' as to remove the forward end of each blade. The cutter then looks like the structure illustrated in Figure 2, each blade having a cross-section somewhat as illustrated in Figure 6.

In cutting off the forward portion of each blade a slight bevel I8 is preferably provided, as shown, somewhat exaggerated, in Figure 6, so as to provide pockets for welding material as will be described hereinafter.

For replacing the worn portion of the blades which have been removed as indicated, a curved strip or cutting edge 19, shown in Figure 8 is fabricated from the same material as was used in the original cutter (cast steel being the usual material) The cutting strip I9 is made exactly in accordance with the dimensions and shape of the corresponding portion of the original cutter. Accordingly, it may be placed along the forward edge of a blade as indicated in Figure 7, and welded thereto, the welding material 20 filling the pockets formed by the beveled edges I8 on the main body of the blade and the similar rear edges 2! on the cutting strip I9.

In order that the re-formed blade may be identical with that on the original cutter, the cutting strip l9 must be very accurately positioned. To

properly position it, a second templet 22 is provided. This templet may be similar to the templet l5 shown in Figure 4, except that it extends farther forward on the blade and serves to locate the forward edge of the cutting strip, preferably by means of a front flange 23 (Figure '7), as well as serving to position the top surface of the cutting strip so that during the initial welding, the cutting strip l9 will be held in alignment with the inner and outer surfaces of the main part of the blade and will be properly spaced therefrom.

Thus the new cutter will have exactly the same shape that the original had before it was worn while the cost of the re-formed structure has been found to be but a fraction of the cost of a new one.

While the process and means for re-forming the cutter have been described here in some detail, and are illustrated as applied to only one kind of cutter, it is obvious that various changes may be made, both in the process and means without departing from the spirit of the invention or the scope of the annexed .claim.

I claim:

The method of re-forming a worn blade of a cutter for a hydraulic dredge which consists in preforming two templets to correspond in shape with portions of the cutter blade before it is worn, using one of said templets to mark a line on the worn cutter blade in parallel to and a short distance from the line of the original cutting edge of said. blade before it became worn, cutting off the portion of the blade between said line and the worn cutting edge, fabricating a body having a cutting edge along one side and a back portion adapted to be welded to the remainder of said blade and welding said body to said remainder of the blade while holding said body and'said remainder in position with the other of said templets.

- W. R. EWING. 

